Dear Dr. Jeff: I just got over a mild case of mono, but haven't been cleared to play hockey. How come? ?M.P.
Dear M.P.: Infectious mononucleosis is a very common illness among college students, and we're currently working our way through the third "epidemic" wave of the school year. For most students, mono lasts two to three weeks, causing a badly sore throat, painfully swollen cervical lymph nodes ("glands"), fever, and fatigue. Some get off easier, with a milder and shorter course, and some get hit harder with a debilitating illness that can drag on for months.
Mono is caused by Epstein Barr Virus (EBV), a member of the herpes virus family. EBV infects the cells which line your nose and throat, as well as B cell lymphocytes (one type of white blood cell). Viral DNA is incorporated into B cell DNA, and these transformed B cells carry the infection to other organs in your body, especially your liver and spleen.
Early childhood infection with EBV is common (pretty much the norm in the developing world), and usually results in a barely noticeable "cold." In the United States, about 30 percent of children have been infected by age five, and another 25 percent by the end of high school. About 12 percent of susceptible college-age men and women are infected each year with EBV, and about half of them develop full-blown mono. That means that nearly one in 40 college students will come down with mono every year.
Transmission of EBV occurs through contact with infected saliva (hence mono as the "kissing disease"). The incubation period is about 30 to 45 days, and the period of communicability can be quite prolonged, with viral shedding beginning during the incubation period and persisting for a year or more after the infection has apparently resolved.
There is no cure for EBV. Fortunately, mono does not usually need to be treated. Sometimes it causes so much painful swelling of your tonsils that a brief course of steroids is necessary. Most often, treatment is supportive: rest and plenty of fluids. Mono causes inflammation of your liver, so alcohol and medications which can affect your liver (e.g. Tylenol and Accutane) must be avoided.
Back to your question, M.P. We tell all students with mono not to participate in any athletics, especially contact sports, for four weeks after diagnosis. There are two reasons for this policy.
First, exercise will likely prolong your illness and delay your recovery. To get well, and to get well as quickly as possible, you need to rest, drink those fluids, and give your body the support it needs to fight off the infection.
Second, virtually all cases of mono involve your liver and spleen. Ultrasound studies have shown that even if swelling of your liver and spleen are not clinically discernible by physical exam, they are nonetheless present essentially 100 percent of the time. When your spleen swells, it extends down below the protection of your ribs. And although spleenic rupture is a relatively rare complication of mono (maybe one in 500 cases), it can be catastrophic and sometimes fatal. Hence the rationale for avoiding any contact activities that might put you and your spleen at increased risk for trauma and rupture. This is the very same rationale behind avoiding any activities or situations that tend to increase intra-abdominal pressure?whether those be sit-ups or, for that matter, constipation.
Very fortunately, swelling of your liver and spleen resolves almost universally within four weeks. This can be confirmed by a physical exam or by an ultrasound, if necessary.
So, M.P., please try to be patient! You don't want to set yourself up for a prolonged recurrence of your illness, and you certainly don't want to take any chances on rupturing your spleen. Four weeks may seem like a very long time, but it's the least you owe yourself.
Be well!
Jeff Benson, M.D.
Dudley Coe Health Center